Monitoring N : P Ratio and Cd, Cu, Pb, and Zn Contents in Different Types of Anaerobic Digestates: A Six-Year Study Case (original) (raw)
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Monitoring N : P Ratio and Cd, Cu, Pb, and Zn Contents in Different Types of Anaerobic Digestates
2020
Depending on the quality of the input substrates, process parameters, and postfermentation treatments, digestates may contain a broad spectrum of potentially toxic elements. We suspected that these contents may vary on a broad scale even under seemingly stable process conditions at the biogas plant. Digestates from four biogas plants were therefore continuously analyzed for their contents of phosphorus, nitrogen, cadmium, copper, lead, and zinc over a period of six years. The input substrates varied between the plants (e.g., cattle and pig slurry and rye and maize silage), but were the same for each plant over the whole period. The N : P ratio of the digestates ranged from 2 to 24, with the digestate coming from cofermentation of pig slurry and energy crops ("DG Pig") having the widest range of N : P ratio over the years. Heavy metal loads of all digestates and during all evaluations did not exceed the limits set by European or German legislation, but as previously expecte...
The Role of Trace Elements on Anaerobic Co-digestion in Biogas Production
In this study, we investigated the concentration of trace elements in the digestates in a laboratory batch anaerobic digester. Many of these trace elements are important macro and micro nutrients. The availability of these nutrients for microbes responsible for anaerobic digestion and substrate toxicity have to be controlled in biogas production. The analyzed substrates were characterized at various concentrations in the following trace elements; potassium, phosphorus, manganese, copper, calcium, molybdenum, zinc, cobalt, iron, aluminum, silver, nickel and cadmium. Trace elements like copper, silver, nickel, cadmium, zinc have been reported to be inhibitory and toxic under certain conditions in biochemical reaction depending on their concentrations. These trace elements lower biogas production above threshold concentration due to accumulation of organic acid as a result of methanogenic bacterial inhibition. There was no deficit of nutrients detected in the anaerobic digesters analysis.
Journal of Cleaner Production, 2019
The use of trace metals as additives to the biogas production process to increase the biogas yield has been identified as a very common approach. Such additives can biostimulate the methanogenic bacteria to increase the biogas and methane production from the anaerobic digestion (AD) of livestock manure. The environmental impact of using the trace elements as manure additives still not evaluated. The objective of this paper is to conduct a comparative environmental impact evaluation of manure treatment with different trace elements for biogas production. The trace metals under evaluation were in the form of the chlorides of nickel (Ni), cobalt (Co) and iron (Fe) which were used as additives to the anaerobic digestion of livestock manure. The results were shown in the form of the specific impacts on global warming and greenhouse gas (GHG) emissions mitigation of producing and utilizing biogas as a bioenergy source. The results of this investigation show that the use of 1 g/m 3 cobalt chloride (CoCl 2) causes the lowest greenhouse gas emissions among all other evaluated trace metals which were calculated on the basis of CO 2-equivalent. An important observation is that the greenhouse gas emissions from the electricity generated using biogas produced without any additives, i.e. without trace metals, were the highest among all other variants/scenarios.
THE INFLUENCE OF HEAVY METALS ON BIOGAS PRODUCTION DURING THE ANAEROBIC DIGESTION PROCESS
Availability of heavy metals plays a very significant role in the performance and stability of biogas digesters, which are operated with energy crops, organic fraction of municipal solid wastes or any other type of organic waste. Heavy metals are present in significant concentrations in animal manure and in some industrial wastewaters. Heavy metals can be stimulatory, inhibitory, or even toxic in biochemical reactions, depending on their concentrations. A trace level of many metals is required for activation or functioning of many enzymes and co-enzymes. Excessive amounts, however, can lead to inhibition or toxicity, .
2015
Article history: Received: February 2015 Received in the revised form: April 2015 Accepted: April 2015 The aim of the study was to identify and assess the impact of four diges- tive masses obtained from different organic substrates on the content of heavy metals in soil. The study utilized soil derived from fertilizer and equipment. Timothy grass was used as a test plant. The effect of a fertilizer on the analyzed mass was compared with the objects of reference, which were: a control object (without fertilization), fertilized objects with the use of ammonium nitrate, fresh pig slurry and mineral fertilizer YaraMila. Experiment was conducted in quadruplicate, consist- ing of the total of 76 objects. Based on the survey, it was found that the use of digestive for fertilizing purposes is justified because of its impact on various soil parameters and is comparable to the impact of traditional fertilizers such as manure, ammonium nitrate and mineral compound fertilizers. The use of the d...
Abundance of trace elements in demonstration biogas plants
Biosystems Engineering, 2011
Ten biogas plants across Europe were investigated for the concentrations of trace elements in their digestates. Many of these trace elements are important micro nutrients and act as microbial agents responsible for the anaerobic digestion of organic material. Great variations in concentrations from biogas plant to biogas plant were found covering a range of 1e2 orders of magnitude. No deficit of nutrients was detected in any of the biogas plants tested, but those plants with high inputs of energy crops and manure had lower values. Also biogas plants feeding high amounts of glycerol in addition to their agricultural feedstock generally showed low concentrations of micro nutrients. The highest concentrations of nutrients were detected at biogas plants fed by bleaching earth. Biogas plants fed with wastes like blood, kitchen and food waste also revealed higher concentrations of micro nutrients.
Journal of Environmental Management, 2019
Heavy metals (HMs), which accumulate in digestion substrates, such as plant residues and livestock manure, can affect biogas yields during anaerobic digestion (AD). Low concentration of Cu 2+ (0-100 mg/L), Fe 2+ (50-4000 mg/L), Ni 2+ (0.8-50 mg/L), Cd 2+ (0.1-0.3 mg/L), and Zn 2+ (0-5 mg/kg) promote biogas production, while high concentrations inhibit AD. Trace amounts of HMs are necessary for the activity of some enzymes. For example, Cu 2+ and Cd 2+ serve as cofactors in the catalytic center of cellulase and stimulate enzyme activity. High contents of Cd 2+ and Cu 2+ inhibit enzyme activity by disrupting protein structures. Trace amounts of HMs stimulate the growth and activity of methanogens, while high levels have toxic effects on methanogens. HMs affect the hydrolysis, acidification, and other biochemical reactions of organics in AD by changing the enzyme structure and they also impact methanogen growth. A better understanding of the impact of HMs on AD can provide valuable insights for improving the digestion of poultry manure and plant residues contaminated with HMs, as well as help mitigate HMs pollution. Although several studies have been conducted in this field, few comprehensive reviews have examined the effect of many common HMs on AD. This review summarizes the effects of HMs on the biogas production efficiency of AD and also discusses the effects of HMs on the activities of enzymes and microbial communities.
Evaluation of Heavy Metals Influence on Biogas Production
Environmental Research, Engineering and Management, 2013
Heavy metals play a very significant role in the performance and stability of biogas digesters, which are operated with organic fraction of municipal solid wastes or any other type of organic waste. For this reason this paper tries to evaluate the impact of heavy metals on biogas yield and quality. Anaerobic digestion of sewage sludge and rapeseed cake mixture has been carried out for 14 days. The obtained data show that the greatest negative impact on biogas production was made by zinc additive. Meanwhile, methane content in biogas varied from 64.5 to 70%.
Elemental composition of biogas residues: Variability and alteration during anaerobic digestion
Biomass and Bioenergy, 2014
Keywords: Digestate Heavy metals Nutrients Biogas plant feedstock Element balance Element recovery a b s t r a c t Biogas production and the amount of thereby incurred digestates increased remarkably in the last decade. Digestates should be used as soil fertilizers to close nutrient cycles. However, knowledge about the elemental composition of digestates from biogas production and element losses or accumulations during fermentation process is insufficient so far. Intending to enlarge the database for the elemental composition of digestates and to investigate element in-and outputs of biogas fermenters, we measured the concentrations of C, N, P, K, S, Ca, Mg, Fe, Mn, Zn, Cu, Pb, Cd, Ni, Mo and Se of digestates and feedstock (ingestates) of four full-scale biogas plants in Germany monthly over a one year period.
Biomass and Bioenergy, 2011
The availability of trace metals as micro-nutrients plays a very significant role on the performance and stability of agricultural biogas digesters, which are operated with energy crops, animal excreta, crop residues, organic fraction of municipal solid wastes or any other type of organic waste. The unavailability of these elements in biogas digesters is probably the first reason of poor process efficiency without any other obvious reason, despite proper management and control of other operational and environmental parameters. However, trace metal requirements of biogas digesters operated with solid biomass are not often reported in literature. Therefore, the aim of this article is to review the previous and current literature about the trace metal requirements of anaerobic biogas digesters operated with solid organic substrates for production of methane.